Ticket #56336: 56336.diff

src/wp-includes/sitemaps/class-wp-sitemaps-registry.php

@@ -65 +65 @@
          * @return WP_Sitemaps_Provider|null Sitemap provider if it exists, null otherwise.
          */
         public function get_provider( $name ) {
-                if ( ! isset( $this->providers[ $name ] ) ) {
+                if ( ! is_string( $name ) || ! isset( $this->providers[ $name ] ) ) {
                         return null;
                 }
 

src/wp-includes/taxonomy.php

@@ -337 +337 @@
 function taxonomy_exists( $taxonomy ) {
         global $wp_taxonomies;
 
-        return isset( $wp_taxonomies[ $taxonomy ] );
+        return is_string( $taxonomy ) && isset( $wp_taxonomies[ $taxonomy ] );
 }
 
 /**